Gas Connections - Modine Manufacturing PDP Installation And Service Manual

InsTAllATIon

gAs ConneCTIons

WARNING
1. All field gas piping must be pressure/leak tested prior to
operation. Never use an open flame. Use a soap solution
or equivalent for testing.
2. Gas pressure to appliance controls must never exceed
14" W.C. (1/2 psi).
3. To reduce the opportunity for condensation, the minimum
sea level input to the appliance, as indicated on the serial
plate, must not be less than 5% below the rated input, or 5%
below the minimum rated input of dual rated units.
CAUTION
1. Purging of air from gas lines should be performed as
described in the National Fuel Gas Code, ANSI Z223.1
(NFPA 54) - latest edition or in Canada CSA-B149 codes.
2. When leak testing the gas supply piping system, the
appliance and its combination gas control must be
isolated during any pressure testing in excess of
14" W.C. (1/2 psi).
3. The unit should be isolated from the gas supply piping
system by closing its field installed manual shut-off valve.
This manual shut-off valve should be located within 6' of
the heater.
4. Turn off all gas before installing appliance.
IMPORTANT
To prevent premature heat exchanger failure, the input to
the appliance, as indicated on the serial plate, must not
exceed the rated input by more than 5%.
1. Installation of piping must conform with local building codes,
or in the absence of local codes, with the National Fuel Gas
Code, ANSI Z223.1 (NFPA 54) - Latest Edition. In Canada,
installation must be in accordance with CSA-B149.1.
2. Piping to units should conform with local and national
requirements for type and volume of gas handled, and
pressure drop allowed in the line. Refer to Table 10.1 to
determine the cubic feet per hour (cfh) for the type of gas
and size of unit to be installed. Using this cfh value and
the length of pipe necessary, determine the pipe diameter
from Table 10.2. Where several units are served by the
same main, the total capacity, cfh and length of main must
be considered. Avoid pipe sizes smaller than 1/2". Table
10.1 allows for a 0.3" W.C. pressure drop in the supply
pressure from the building main to the unit. The inlet
pressure to the unit must be 6-7" W.C. for natural gas and
11-14" W.C. for propane gas. When sizing the inlet gas
pipe diameter, make sure that the unit supply pressure
can be met after the 0.3" W.C. has been subtracted. If the
0.3" W.C. pressure drop is too high, refer to the Gas
Engineer's Handbook for other gas pipe capacities.
3. Install a ground joint union with brass seat and a manual
shut-off valve adjacent to the unit for emergency shut-off
and easy servicing of controls, including a 1/8" NPT
plugged tapping accessible for test gauge connection
(see Figure 10.1).
4. Provide a sediment trap before each unit and in the line
where low spots cannot be avoided (see Figure 10.1).
5. When Pressure/Leak testing, pressures above 14" W.C.
(1/2 psi), close the field installed shut-off valve, disconnect
the appliance and its combination gas control from the
gas supply line, and plug the supply line before testing.
When testing pressures 14" W.C. (1/2 psi) or below, close
the manual shut-off valve on the appliance before testing.
10
figure 10.1 - recommended sediment Trap/manual
shut-off valve Installation for gas Connection
SUPPLY LINE
GAS
SUPPLY LINE
3"
MIN.
SEDIMENT
Manual shut-off valve is in the "OFF" position when handle is perpendicular
➀
to pipe.
Table 10.1 - manifold Pressure & gas Consumption ➀
manifold Pressure
model size
("W.C.)
150 Gal/Hr. Propane
Orifice Drill Size
175 Gal/Hr. Propane
Orifice Drill Size
200 Gal/Hr. Propane
Orifice Drill Size
250
Gal/Hr. Propane
Orifice Drill Size
300
Gal/Hr. Propane
Orifice Drill Size
350
Gal/Hr. Propane
Orifice Drill Size
400 Gal/Hr. Propane
Orifice Drill Size
Table 10.2 - gas Pipe Capacities - natural gas
Pipe
length (ft)
1/2" 3/4"
10
132 278
20 92 190
30 73 152
40 63 130
50 56 115
60
50 105
70
46 96
80
43 90
100
38 79
125 34 72
150 31 64
Capacities in Cubic Feet per Hour through Schedule 40 pipe with maximum
➀
0.3"W.C. pressure drop with up to 14"W.C. gas pressure. Specific gravity is 0.60
for Natural gas and 1.50 for Propane gas.
For Pipe Capacity with Propane Gas, divide Natural gas capacity by 1.6. Example:
➁
What is the propane gas pipe capacity for 60' of 1-1/4" pipe? The Natural gas
capacity is 400 CFH. Divide by 1.6 to get 250 CFH for Propane gas.
6-580.7
GAS
GROUND
JOINT
UNION
W/ BRASS
SEAT
➀
MANUAL GAS
SHUT-OFF VALVE
TO
CONTROLS
PLUGGED
1/8" NPT TEST
GAGE CONNECTION
TRAP
natural Propane
3.5 10
CFH 138.1 58.0
- 1.64
21 39
CFH 166.7 70.0
- 1.86
28 43
CFH 190.5 80.0
- 2.19
25 42
CFH 238.1 100.0
- 2.74
18 36
CFH 285.7 120.0
- 3.29
21 39
CFH 333.3 140.0
- 3.84
23 41
CFH 381.0 160.0
- 4.38
25 42
natural gas
1" 1-1/4" 1-1/2"
520 1050 1600 3050
350 730 1100 2100
285 590 890 1650
245 500 760 1450
215 440 670 1270
195 400 610 1150
180 370 560 1050
170 350 530 930
150 305 460 870
130 275 410 780
120 250 380 710
# of
orifices
2
3
3
3
4
5
6
➀ ➁
2"